When a medical diagnosis is accomplished with X-ray examination, it is often desirable to complete the examination during a single visit of a patient to a diagnostic X-ray room. Recall of a patient to repeat or supplement an examination is undesirable for a number of reasons. They include (a) time lost in obtaining the information necessary for proper medical diagnosis where time can be of the essence; (b) repetition of some procedures such as catheter insertion can be dangerous; (c) patient discomfort which can be quite acute if the patient is severely ill; and, (d) inefficient utilization of X-ray equipment.
With modern medical diagnostic procedures it is not uncommon to develop and preliminarily examine a radiograph while a patient remains at an exposure station in a diagnostic X-ray room. This permits the attending physician to be satisfied that a given X-ray examination procedure has been successfully completed or alternatively must, for some reason, be augmented by taking further radiographs.
If radiographs are to be inspected while a patient remains at an exposure station, fast film processing has come to be considered a virtually necessary part of medical X-ray diagnostic procedures. To achieve high rates or processing, film processors have been developed which automatically process the exposed sheet of film by mechanically feeding the sheet of film in sequence through the baths of developer and fixer solutions, then washing and drying it. The time required for completely processing a radiograph is of the order of one-half minute or less. An improved film processor of this type is described in the reference FILM PROCESSOR patent.
Chemicals which perform the developing and fixing are consumed by use. With manual film processing, a skilled technician can compensate for depletion in solution concentrations by retaining films in the solutions for longer periods of time. With automatic processors, on the other hand, processing times are substantially constant and as a consequence, if solution concentrations are allowed to become depleted, the inevitable result is poor quality.
Accordingly, providing fast film processing of the requisite high quality and at the high volumes which are often encountered in busy hospitals depends on the provision of fresh, clean, and properly mixed chemicals. As the sheets of the film are transported through the baths, solution is carried away by the sheets and chemicals are consumed. Thus, fresh chemicals are required if desired processing quality is to be maintained and replenishment is a necessity.
With the processor of the FILM PROCESSOR patent, replenishing quantities of developer and fixer solutions are supplied automatically during processing of film on an as-needed basis.
The developer and fixer solutions have relatively short shelf-lives; accordingly, it is desirable to mix the developer and the fixer solutions (1) near the location of the film processor and (2) at times immediately prior to the demand for them by the film processor.